User:Prtksxna/toc.js

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Documentation for this user script can be added at User:Prtksxna/toc. This user script seems to have an accompanying .css page at User:Prtksxna/toc.css.

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( function ( $ ) {
	
$( function () {
	var $toc = $( '#toc' ),
		$window = $( window ),
		$mwPanel = $( '#mw-panel' ),
		tocLimit = $toc.offset().top + $toc.height(),
		$floatTOC = $toc
			.clone()
			.attr( 'id', '')
			.addClass( 'floatTOC' )
			.appendTo( 'body' )
			.css( 'height', $window.height() )
			.hide(),
		headingsOffset = [];
		
	// Get all heading positions
	$('.mw-headline').each( function() { 
		headingsOffset.push( [ $(this).attr( 'id' ), $( this ).offset().top ] );
	} );
	
	// For the window scroll event
	var scroller = function () {
		var scrollTop = $window.scrollTop();
		if ( scrollTop > tocLimit ) {
			$floatTOC.show();
			$mwPanel.hide();
			
			// Highlight current
			$floatTOC.find( 'a' ).css( 'font-weight', 'normal' )
			var highlight = "";
			$.each( headingsOffset, function ( i, v ) {
				if ( scrollTop < v[ 1 ]) {
					highlight = headingsOffset[ i -1 ][ 0 ];
					return false;
				}
			} );
			$floatTOC.find( 'a[href="#' + highlight + '"]' ).css( 'font-weight', 'bold' );
			
		} else {
			$floatTOC.hide();
			$mwPanel.show();
		}
	}
	
	$window.on( 'scroll', $.throttle( 250, scroller ) );
} );

} ) ( jQuery );